ISO 13357-1:2017

Overview

ISO 13357-1:2017 - Petroleum products - Determination of the filterability of lubricating oils - Part 1: Procedure for oils in the presence of water - specifies a laboratory test method to evaluate how mineral-based lubricating oils (especially hydraulic oils) pass through fine filters when contaminated with water. The standard defines a controlled procedure, required reagents and apparatus, and two stage measurements (Stage I and Stage II) to quantify filterability as a dimensionless percentage. The method has been evaluated for oils up to ISO viscosity grade (VG) 100 (ISO 3448).

Key topics and technical requirements

• Scope and limitations: Applies to mineral-based oils; not suitable for some fire‑resistant fluids or oils with insoluble/partially soluble additives or very large molecular species. Evaluated up to VG 100.
• Two-stage measurement:
  • Stage I compares filtered volume against an ideal, unblocked membrane benchmark.
  • Stage II compares early filtration flow rate with flow near 200–300 ml - more sensitive to gels and fine silts.
• Test principle: Oils are heat‑soaked with a defined amount of water, filtered under specified pressure through a membrane, and filtration times for set volumes recorded. Results are averages of three determinations.
• Apparatus and materials:
  • Mixed cellulose ester membrane filters, diameter 47 mm, mean pore size 0.8 µm.
  • Stainless-steel filtration assembly with an effective filtration area specified in the standard.
  • Reagents such as ISO Grade 3 water, isopropyl alcohol and a light aliphatic hydrocarbon wash solvent.
  • Oven (70 °C ± 2 °C), measuring cylinders, pressure regulator, timing device.
• Test report and validity: Specifies calculation methods, criteria for test validity and precision, and required report content.

Applications and practical value

• Product development: Evaluate new hydraulic lubricants for susceptibility to filter plugging when contaminated with water.
• Quality control and acceptance testing: Routine lab tests for manufacturers and suppliers to demonstrate filterability performance.
• Failure analysis and field assessment: Predict filtration behaviour in systems that use very fine filters (<5 µm) and assess risks from water ingress.
• Procurement and OEM specifications: Enables equipment manufacturers and end-users to set filterability requirements for hydraulic fluids.

Who should use this standard

• Lubricant manufacturers and formulators
• Independent testing laboratories
• Hydraulic system OEMs and maintenance engineers
• Quality assurance and product compliance teams

Related standards

• ISO 13357-2 - Filterability testing in dry conditions (complementary method)
• ISO 3448 - ISO viscosity classification (viscosity grades)
• ISO 3696, ISO 4788, ISO 6614 - referenced for laboratory water quality, glassware and separability/test equipment

Keywords: ISO 13357-1:2017, filterability, lubricating oils, hydraulic oils, water contamination, membrane filtration, ISO viscosity grade, test procedure.